JP6595962B2 - Edge server, session sharing system, method and program - Google Patents

Description

  The present invention relates to an edge server, a system, a method, and a program that share session data with a terminal.

  With the spread of Internet of Things (IoT), not only terminals such as PCs (Personal Computers) and smartphones but also many M2M (Machine to Machines) devices such as surveillance camera image sensors and motion sensors are clients. It is expected to be connected to a server installed on the Internet as a terminal.

In such a situation, an increase in traffic load becomes a problem in a conventional cloud computing environment in which services are provided by a cloud server installed in a centrally deployed data center or the like. For example, there is a problem that a delay time allowed in a service that requires real-time property cannot be satisfied, or that a large amount of data flows from a client terminal, the network is congested, resulting in data being discarded.
Therefore, data generated from client terminals is processed by edge servers distributed near the site where many client terminals are deployed, for example, near base stations of mobile terminals, and traffic and response times to client terminals are reduced. Mobile edge computing has been proposed.

  In mobile edge computing, it is required to manage session data (for example, session ID) on the edge server side. When edge servers are distributed and deployed for each base station, when a client terminal is handed over, the edge server does not respond for a certain period of time, and the login state cannot be maintained. Requires that the edge servers share session data.

Examples of techniques for suppressing session disconnection include the following methods 1 to 3 disclosed in Patent Document 1.
Method 1 is called a sticky session method, and the session data sharing server arranged in the mobile network manages the IP address and session data of the edge server A to which the client terminal is connected for the first time. In this method, even if the nearest server changes to the edge server B due to the handover of the client terminal, the edge server A that is connected for the first time continues processing. By continuing processing with a specific single server that has issued a session ID, session disconnection is suppressed.

  Method 2 is called a session replication method, and the edge server A and the edge server B share session data without going through the session data sharing server. In this method, when the nearest edge server changes due to the handover of the client terminal, the session data is copied from the edge server A to the nearest edge server B, and the edge server B continues processing. By copying the session ID and the IP address of the client terminal from the edge server A to the edge server B within a predetermined time and continuing the processing at the edge server B, the login state is maintained, and session disconnection is suppressed.

  Method 3 is called a session sharing method, and the edge server A and the edge server B share session data via the session sharing server. In this method, when the nearest edge server changes due to the handover of the client terminal, the session data is copied from the session data sharing server to the nearest edge server B, and the edge server B continues processing. The session ID and the IP address of the client terminal are copied from the session sharing server to the edge server B, and the process is continued at the edge server B, thereby suppressing session disconnection.

Special table 2013-532333 gazette

  By the way, the client terminal may perform streaming that simultaneously reproduces video data such as game video while downloading from the edge server. In streaming, a still image (frame) of a specified number of frames per unit time is drawn. For example, when the frame rate is 60 fps, the frame is drawn every 16.67 msec (= 1,000 msec / 60 frame). The

Here, when a client terminal is handed over while streaming 60 fps video data (user data) and the edge server to be connected is switched, if the session sharing between the edge servers takes 16.67 msec or more, the video data Download and playback are temporarily interrupted, causing problems such as video interruptions and operation delays.
In the above-described methods 1 to 3, it takes time to share session data between edge servers, and the responsiveness of the client terminal may be temporarily lowered at every handover.
When an edge server is arranged for each base station, the distance between the base stations is 500 m (example: urban area) to several km (example: other than urban area). There could be a problem.

  An object of the present invention is to provide an edge server, a session sharing system, a method, and a program capable of suppressing session disconnection and improving the responsiveness of the client terminal when the client terminal connects to another edge server by handover. Objective.

  An edge server according to the present invention monitors a start and end of a handover between a base station, a storage unit that stores session information established with a client terminal, and a handover destination base station to a handover destination base station A monitoring unit for acquiring data transferred to the mobile station, and an adding unit for adding the session information to a free area of a packet in transmission data requested via the handover source base station until the handover is completed, An acquisition unit for acquiring the session information from the transmission data transferred to the handover destination base station and storing the session information in the storage unit.

  The adding unit may select a communication layer having a free area in a packet header among a plurality of communication layers according to a protocol of the transmission data.

  The adding unit may preferentially select a lower layer among the plurality of communication layers.

  A session sharing system according to the present invention is a session sharing system having a plurality of base stations and an edge server arranged in each of the base stations, and the base station responds to the handover of the client terminal by the client terminal. The edge server includes a storage unit for storing session information established with the client terminal, and start and end of handover between the base stations. A monitoring unit that acquires data transferred from the handover source base station to the handover destination base station, and a packet in transmission data requested via the handover source base station before the handover is completed. An adding unit for adding the session information to the free space of From the transmission data transferred to Dooba destination base station, it obtains the session information, and an acquisition unit to be stored in the storage unit.

  In a session sharing method according to the present invention, in a session sharing system having a plurality of base stations and an edge server arranged in each of the base stations, the edge server stores session information established with a client terminal. A storage step, an adding step of adding the session information to an empty area of a packet in transmission data requested via the base station of the handover source, before the handover between the base stations is completed, An acquisition step of acquiring the session information from the transmission data transferred from the base station to the handover destination base station.

  A session sharing program according to the present invention stores session information established with a client terminal in the edge server in a session sharing system having a plurality of base stations and an edge server arranged in each of the base stations. A storage step, an adding step of adding the session information to an empty area of a packet in transmission data requested via the base station of the handover source, before the handover between the base stations is completed, An acquisition step of acquiring the session information from the transmission data transferred from the base station to the handover destination base station.

  According to the present invention, when a client terminal connects to another edge server by handover, session disconnection is suppressed, and the responsiveness of the client terminal is improved.

1 is a diagram illustrating an overall configuration of a session sharing system according to an embodiment. It is a figure which illustrates the session data memorize | stored in the session table which concerns on embodiment. It is a sequence diagram which shows the session sharing method which concerns on embodiment.

Hereinafter, an example of an embodiment of the present invention will be described.
FIG. 1 is a diagram showing an overall configuration of a session sharing system 1 according to the present embodiment.
The session sharing system 1 includes a plurality of edge servers 10 (10a and 10b), a base station 20 (20a and 20b), and a client terminal 30.

When the client terminal 30 is handed over, if the connection is switched to the base station 20b before the user data transmitted from the edge server 10a is received from the base station 20a, the user data (unreachable data) is stored in the base station 20a. To the client terminal 30 directly. Therefore, according to the 3GPP standard specification (3GPP TS 36.423 V8.0.0 (2007-12)) of the mobile network, each base station 20 is provided with an X2AP interface 21.
Along with the X2 handover, the base station 20a wirelessly transfers unreachable data to the base station 20b through the X2AP interface 21, and the base station 20b transfers unreachable data to the client terminal 30 during handover. Will continue to communicate.

  As the client terminal 30 moves, the client terminal 30 connects to one of the nearest base stations 20 and exchanges data with the edge server 10 provided corresponding to each base station 20. The client terminal 30 is an information processing apparatus such as a smartphone, a mobile phone, or a tablet terminal.

The edge server 10 includes a session table 11 (storage unit), a monitoring unit 12, an addition unit 13, and an acquisition unit 14.
The session table 11 stores session data established with the client terminal 30.

FIG. 2 is a diagram illustrating session data stored in the session table 11 according to the present embodiment.
In the session table 11, for example, as shown in the figure, the session ID “333” issued by the edge server 10 and the IP address “9.9.9.9” of the client terminal 30 are stored in association with each other. .

  The monitoring unit 12 has an RNIS (Radio Network Information Services) function for monitoring the start and end of X2 handover in the base station 20, and is transferred from the handover source base station 20a to the handover destination base station 20b by the X2AP interface 21. The obtained packet data is provided to the acquisition unit 14.

The adding unit 13 makes a session in an empty area (optional area) of a packet header in unreachable data that is requested via the handover source base station 20a and transferred to the handover destination base station 20b before the handover is completed. Data (for example, session ID) is added.
Specifically, the adding unit 13 identifies an option area that is a free area of the header by analyzing the packet configuration of unreached data, and appends the session data to the option area (for example, the option area of the HTTP header), Generate as a packet of unreached data. An existing packet editing / processing tool may be used for this function.

In addition, the adding unit 13 selects a communication layer having a free area larger than the capacity of the session data in the packet header, from among a plurality of communication layers, according to the protocol of unreached data transferred between the base stations 20.
At this time, the adding unit 13 preferentially selects a lower layer among the plurality of communication layers.

The acquisition unit 14 acquires session data from the packet header of unreached data transferred to the handover destination base station 20 b and stores the session data in the session table 11.
Specifically, the acquisition unit 14 identifies an option area of the header by analyzing the packet structure of unreached data, and reads the data in the option area. This function is realized by adding an option area reading method as a software program to the reception function among the existing functions that are transmitted and received by a specific protocol such as HTTP.

FIG. 3 is a sequence diagram showing a session sharing method in the session sharing system 1 according to the present embodiment.
In step S1, the client terminal 30 establishes a connection with the nearest base station 20a, and the edge server 10a issues session data (for example, session ID: 333).

  In step S2, the edge server 10a stores the issued session data (session ID: 333, client terminal IP address: 9.9.9.9) in the session table 11.

  In step S3, the client terminal 30 transmits a request for user data # (N-1) to the edge server 10a. Note that # (N-1) is a number assigned to one frame of moving image data such as a cloud game, for example, and # 1, # 2,..., # (N-1), # (N ) (N is a natural number) in ascending order.

  In step S4, the client terminal 30 leaves the base station 20a and moves closer to the base station 20b.

  In step S5, when the base station 20b detects that the radio field intensity of the client terminal 30 to the base station 20b is larger than the radio field intensity of the client terminal 30 to the base station 20a, the base station 20a and the base station X2 handover with 20b is started.

  In step S6, the edge server 10a and the edge server 10b each detect the start of the X2 handover by the monitoring unit 12.

  In step S7, the addition unit 13 of the edge server 10a adds the session data to the option area of the header of the user data # (N-1) responding to the client terminal 30 because the handover is started at the base station 20a. To do.

  In step S8, the edge server 10a transmits the destination of the user data # (N-1) to be responded to the base station 20a as the client terminal 30.

  In step S9, when the base station 20a detects that the client terminal 30 is not connected and has moved to the base station 20b, the user data # (N-1) responding to the client terminal 30 is transmitted to the base station 20b by X2AP. Transfer by the interface 21.

  In step S10, the acquisition unit 14 of the edge server 10b acquires session data from the option area of the header of user data # (N-1) transferred from the base station 20a to the base station 20b by X2 handover.

  In step S11, the acquisition unit 14 of the edge server 10b stores the session data acquired in step S10 (session ID: 333, client terminal IP address: 9.9.9.9) in the session table 11.

  In step S12, the user data # (N-1) that has become unreachable data that cannot be directly transferred from the base station 20a to the client terminal 30 is transferred to the client terminal 30 via the base station 20b.

  In step S13, the X2 handover between the base station 20a and the base station 20b ends.

  In step S14, the edge server 10a and the edge server 10b each detect the end of the X2 handover by the monitoring unit 12.

  In step S15, the client terminal 30 transmits a request for user data # (N) to the edge server 10b. At this time, session data (session ID stored in Cookie or the like) is also transmitted to the edge server 10b.

  In step S16, the edge server 10b transmits the session data transmitted from the client terminal 30 and the record (session ID: 333, client terminal IP address: 9.9.9.) Stored in the session table 11 by the edge server 10b. Confirm that 9) matches.

  In step S <b> 17, the edge server 10 b transmits user data # (N) to the client terminal 30.

  According to the present embodiment, the edge server 10a adds the session data issued and stored by the edge server 10a to the client terminal 30 to the header of unreached data when the client terminal 30 performs handover. When the handover destination edge server 10b acquires and stores the session data, the client terminal 30 can continue communication with the edge server 10b without disconnecting the session.

Also, if the base station 20a and the base station 20b are macro cell base stations, the distance between base stations is several hundred to several km. For example, if the distance between base stations is 9 km, the time for sharing session data in step S9 is Distance between base stations / Radio wave speed = 9 km / (300,000 km / sec) = 0.00003 sec = 0.03 msec.
Therefore, the session data sharing time between the edge servers is, for example, less than 16.67 msec for drawing a moving image frame of 60 fps. As a result, the problem that the reproduction of the moving image is stuttered or temporarily interrupted every handover is solved, and the responsiveness of the client terminal 30 is improved.

  As described above, since the sharing time of the session data between the edge servers 10 is reduced, the responsiveness in the client terminal 30 is improved in a use case for handling session data in addition to a high frame rate moving image.

  Furthermore, since the edge server 10 selects a communication layer having a free area in the packet header from a plurality of communication layers according to the protocol of unreachable data transferred between the base stations 20, the communication method is limited. In addition, session data can be shared in a short time using an appropriate communication layer.

  At this time, since the edge server 10 preferentially selects a lower layer among the plurality of communication layers, it is possible to notify the session data with a smaller amount of communication data (number of packets) and to shorten the sharing time.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. Further, the effects described in the present embodiment are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the present embodiment.

  The session sharing method by the session sharing system 1 is realized by software. When realized by software, a program constituting the software is installed in an information processing apparatus (computer). These programs may be recorded on a removable medium such as a CD-ROM and distributed to the user, or may be distributed by being downloaded to the user's computer via a network. Furthermore, these programs may be provided to the user's computer as a Web service via a network without being downloaded.

1 Session sharing system 10, 10a, 10b Edge server 11 Session table (storage unit)
DESCRIPTION OF SYMBOLS 12 Monitoring part 13 Addition part 14 Acquisition part 20, 20a, 20b Base station 21 X2AP interface 30 Client terminal

Claims (6)

An edge server located in each base station,
A storage unit for storing session information established with the client terminal;
The start and end of the handover between base stations is monitored, when the base station itself is located is a handover destination, viewed from the handover source base station to the client terminal that has been transferred to the handover destination base station a monitoring unit to get the reach data,
When the base station on which it is located is the handover source, the unreachable data before being requested and transferred to the handover destination base station by the handover source base station before the handover is completed An adding unit for adding the session information to a free area of the packet in
An acquisition unit for acquiring the session information from the unreached data transferred to the handover destination base station and storing the session information in the storage unit when the base station in which the mobile station is located is the handover destination; Provide edge server. The edge server according to claim 1, wherein the adding unit selects a communication layer having a free area in a packet header from a plurality of communication layers according to a protocol of the unreached data.   The edge server according to claim 2, wherein the adding unit preferentially selects a lower layer among the plurality of communication layers. A session sharing system having a plurality of base stations and an edge server arranged in each of the base stations,
The base station
In response to the handover of the client terminal, an interface for transferring unreachable data to the client terminal to the handover destination base station,
The edge server is
A storage unit for storing session information established with the client terminal;
The start and end of the handover between base station monitors, when itself is arranged the base station is the handover destination, said unreached data transferred from the handover source base station to the handover destination base station A monitoring unit to obtain,
When the base station on which it is located is the handover source, the unreachable data before being requested and transferred to the handover destination base station by the handover source base station before the handover is completed An adding unit for adding the session information to a free area of the packet in
An acquisition unit for acquiring the session information from the unreached data transferred to the handover destination base station and storing the session information in the storage unit when the base station in which the mobile station is located is the handover destination; A session sharing system. In a session sharing system having a plurality of base stations and an edge server arranged in each base station, during handover between base stations ,
A storage step in which an edge server arranged in a handover source base station stores session information established with a client terminal;
Adding step the handover source edge server located in the base station of, before the handover is completed, the free space of the packet in the transmission data requested through the handover source base station, to add the session information When,
Handover destination edge server located in the base station of the the transmission data transferred to the handover destination base station from the handover source base station, a session sharing for executing an acquisition step of acquiring the session information Method. In a session sharing system having a plurality of base stations and an edge server arranged in each base station, during handover between base stations ,
A storage step in which an edge server disposed in a handover source base station stores session information established with a client terminal;
Adding step the handover source edge server located in the base station of, before the handover is completed, the free space of the packet in the transmission data requested through the handover source base station, to add the session information When,
Handover destination edge server located in the base station of the the transmission data transferred to the handover destination base station from the handover source base station, to execute the an acquisition step of acquiring the session information Session sharing program.

Images